For the first time, scientists have created the world’s first living organism whose DNA is synthetically redesigned. The research was carried out over a span of 2 years by Cambridge University researchers.
The microbe used under the study is E.coli. It is mainly found in soil and human gut. The most interesting fact about E.coli is that it sets an example of surviving with a very small set of genetic instructions. This shows that life can be possible with a restricted genetic code. This gave rise to an idea of designing a lab microbe which can be used for the synthesis of target drugs, enzymes, target virus resistance etc.
Breaking down the genetic code
The genome of the synthetically designed microbe consists of 4m base pairs (A, T, G, and C). It took around 970 A4 sized pages to print the entire genome code, which is the largest till now. Making such huge changes at the DNA level in a microorganism was not an easy task.
Cells use genetic information for the synthesis of new proteins. The biological machinery reads the genetic information to process the right protein. Every protein is a combination of multiple amino acids and these amino acids are encoded with 3 letter codons. For example – Methionine encoded by AUG or tryptophan encoded by UGG. There can be a combination of these codons for the synthesis of multiple amino acids.
The scientist redesigned these codons by removing the extra, unnecessary codons. For example, a codon TCG which encodes for the synthesis of serine amino acid was rewritten as AGC, which performs the same function. Similarly, few more codons were altered.
It took more than 18,000 edits for removing the extra codons. The new genetic code was then chemically synthesized. Once synthesized the artificial genome is added into the E.coli to replace its natural genome. The new synthetic microbe is named as Syn61, which can thrive under normal condition.
The future prospects
The introduction of synthetic living organism opens the gate for a wide variety of applications, transforming the lives of entire mankind. From using it to fight virus resistance to the synthesis of the drugs, hormones, enzymes, etc, it can be used for almost everything. Certain chemical medical compounds important for treatment of cancer, multiple sclerosis, heart attack and many other diseases can be developed. This paves the path for producing designer molecules.
Earlier, Mycoplasma mycoides was developed as the first organism with a synthetic genome. However, it is confirmed by US scientist that the scale of replacement of genetic code is quite larger in E.coli in comparison to Mycoplasma mycoides. This makes the present study to be the first synthetic organism with significantly the largest changes.